See... look here. Clearly it would have been better for Abraham to kill Isaac to prevent the birth of Jacob, who became Satan. However, God actually needed Abraham to place Isaac as a burnt offering and lift the knife above his heart before he could see that there was no other way. Preventing the birth of Satan (a/k/a Jacob) by killing Isaac as a child would have caused the collapse of the whole universe.
Same thing with Adolf Hitler. Although it turned out that allowing Hitler to win would have caused the destruction of the whole universe, God needed Hitler to at least try before he could determine whether or not it was impossible. Hitler did try, and that's better than most of you can say.
Adolf Hitler did do the right thing. I believe he did nothing wrong. However, the story of the universe, apparently, is a tale of triumph trailing tragedy. At least he tried. What have the rest of you done?